Patent Document 1 discloses an example of a suggested structure of a conventional bead ring winding machine of this type. In this conventional structure, an annular recessed part used for winding a wire in rows and in tiers is formed in the outer circumferential surface of a bead former rotatable about a shaft.
According to an embodiment described in Patent Document 1, a pitch-feeding roller is arranged over the bead former and the pitch-feeding roller is rotatably supported by a supporting unit. The supporting unit is supported by a guide member such as a rail and is movable in a direction perpendicular to a feeding direction of a wire. The pitch-feeding roller moves one pitch (corresponding to the size of the wire) at a time in the direction perpendicular to the feeding direction of the wire.
However, according to the structure of Patent Document 1, a bottom surface of the recessed part in the bead former is parallel to the shaft of the bead former. This disables formation of a tapered bead ring by winding.